Spark plug protector cap



FIG. 1 is a perspective view of one end of a spark plug protector cap according to my design; with dashed line illustrations showing a spark plug with which it would be used, but forming no part of the design;

FIG. 2 is a perspective view thereof from the opposite end;

FIG. 3 is a view of one end thereof;

FIG. 4 is a side view thereof; and,

FIG. 5 is a view of the other end thereof.

The broken line showing of the spark plug in FIG. 1 is included for the purpose of illustrating environmental structure only and forms no part of the claimed design. 

The ornamental design for a spark plug protector cap, as shown and described. 